fix(versioning,docs): stamp .NET assembly version + worker doc drift (TST-11, WRK-15)

TST-11: single-source the .NET-side version in src/Directory.Build.props so
Server/Worker/Contracts/tests stamp 0.1.2 (was the SDK default 1.0.0) and
InformationalVersion carries the git short SHA (0.1.2+<sha>) for support
correlation; the git query is guarded (ContinueOnError) so a build outside a
git checkout still succeeds. Verified: Server assembly stamps 0.1.2+579282f,
build clean. Kept at 0.1.2 (matches Contracts + aligned Python/Rust/Go
clients); Java leads at 0.2.0 post JDK-17 retarget. Convergence to a single
0.2.0 cadence left as a release decision, not forced here.

WRK-15 (docs-only, no x86 worker build needed): correct the STA thread name in
docs/WorkerSta.md + docs/MxAccessWorkerInstanceDesign.md to the actual
MxGateway.Worker.STA (was the FQ ZB.MOM.WW.MxGateway.Worker.STA), and fix the
stale heartbeat-counter note - CaptureHeartbeat now populates event queue depth
(eventQueue.Count) and sequence (LastEventSequence) from the live queue.

Claude-Session: https://claude.ai/code/session_01DMXXvNuPekkkrTEyPNxEkW

src/Directory.Build.props

@@ -9,6 +9,31 @@
     <Deterministic>true</Deterministic>
   </PropertyGroup>
 
+  <!-- TST-11: single-source the .NET-side version for Server, Worker, Contracts, and tests
+       (they otherwise stamp the SDK default 1.0.0, so a deployed gateway cannot be correlated
+       to a release). Kept at 0.1.2 to match the Contracts package and the aligned Python/Rust/
+       Go clients; the Java client leads at 0.2.0 after its JDK-17 retarget. The git short SHA is
+       appended to InformationalVersion (0.1.2+<sha>) so support can map a running binary to a
+       commit; the query is guarded so a build outside a git checkout still succeeds. -->
+  <PropertyGroup>
+    <Version>0.1.2</Version>
+  </PropertyGroup>
+
+  <Target Name="StampSourceRevision"
+          BeforeTargets="GetAssemblyVersion;GenerateAssemblyInfo"
+          Condition="'$(SourceRevisionId)' == ''">
+    <Exec Command="git -C &quot;$(MSBuildThisFileDirectory)&quot; rev-parse --short HEAD"
+          ConsoleToMSBuild="true"
+          StandardOutputImportance="Low"
+          ContinueOnError="true"
+          IgnoreExitCode="true">
+      <Output TaskParameter="ConsoleOutput" PropertyName="_StampedGitSha" />
+    </Exec>
+    <PropertyGroup>
+      <SourceRevisionId Condition="'$(_StampedGitSha)' != ''">$(_StampedGitSha.Trim())</SourceRevisionId>
+    </PropertyGroup>
+  </Target>
+
   <!-- SQLitePCLRaw.lib.e_sqlite3 2.1.11 (transitive via Microsoft.Data.Sqlite) carries GHSA-2m69-gcr7-jv3q,
        which surfaces as NU1903 (warning-as-error). No patched e_sqlite3 release exists yet (2.1.11 is latest),
        so this targeted suppression keeps every OTHER transitive package audited. Remove once an upstream fix ships. -->